package com.baidu.demo;

import java.util.HashMap;
import java.util.Map;

public class Demo01 {
    public static void main(String[] args) {
        Map<String, Object> map = new HashMap<>();
        map.put("name", "zhangsan");
        map.put("name", 20);
        int size = map.size();
        Object name = map.get("name");


        System.out.println(name);
        System.out.println(size);
        System.out.println(map);

    }
}
